The interactions of chronic lymphocytic leukemia cells with the microenvironment in secondary lymphoid tissues and the bone marrow are known to promote CLL cell survival and proliferation

Chronic lymphocytic leukemia (CLL) is the most common type of chronic leukemia, accounting for approximately 40% of all leukemia's and mainly affecting older individuals. As it has a highly variable clinical course, identification of molecular and biological prognostic markers has provided new insights into the risk stratification of patients with CLL .

The interactions of chronic lymphocytic leukemia cells with the microenvironment in secondary lymphoid tissues and the bone marrow are known to promote CLL cell survival and proliferation . CD49d (one of biomarkers) is one of independent prognostic risk parameter in CLL with important roles in shaping these interactions.

CD49d also is one of independent prognostic risk parameters in CLL that predict adverse outcome and linked to processes involved in interaction with the vascular endothelium and/or migration into the extravascular compartments .

The cell-surface glycoprotein CD44 is involved in cell motility, cellular trafficking, and stem cell differentiation . It contributes to the phenotypic hallmarks of many cancers, such as invasiveness, self-renewal, and sustained survival. CD44 transmits both growth and apoptotic signals, a functional duality that is also observed in hematologic malignancies.

CD44 expression in CLL is mediated by the tumor microenvironment. As a coreceptor, CD44 promotes leukemogenesis by regulating stimuli of MCL1 expression. Moreover, CD44 can be addressed therapeutically in CLL by specific antibodies.

Inclusion Criteria:

• All patients are newly diagnosed as CLL

Exclusion Criteria:

• : patients with associated malignancies

30 patients All patients are newly diagnosed as CLL patients with associated malignancies

• Clinical history and clinical examination by the physician.
• Complete blood picture: on peripheral blood sample.
• BM aspiration: allowing diagnosis of the type of leukemia.
• Immunophenotyping by flowcytometer: will be done on peripheral blood or bone marrow aspirate specimens for establishing diagnosis of CLL by detecting its markers ( CD5,CD19,CD23) and for detecting membrane expression of CD49d and CD 44